Observations of Autumnal Cooling in a Large Estuary: The Glider Data from Long Island Sound in 2014

<p>This data file is a component of the data used in a paper to appear in the Journal of Geophysical Research in 2023 entitled &quot;Observations of Autumnal Cooling in a Large Estuary&quot; by Amin Ilia, Grant McCardell, Kay Howard-Strobel, and James O&#39;Donnell.&nbsp; The data file contains the measurements from a Slocum Glider (V1) from Webb Research used in the paper. The data is in&nbsp;a MATLAB binary (.mat) file as a structure variable with a field&nbsp;MetaData containing&nbsp;some notes, and data in&nbsp;<br> &nbsp; &nbsp; SampleTimeEST- the date and time of the sample (EST) in MATLAB&#39;s datenum() format<br> &nbsp; &nbsp; Pressure_dBar - the pressure (or&nbsp;equivalently depth in m) that the sample was acquired&nbsp;<br> &nbsp; &nbsp; Temperature_C - the water temperature in Celcius<br> &nbsp; &nbsp; PracticalSalinty - the practical salinty<br> &nbsp; &nbsp; LatitudeDeg- the latitude of the sampling location (deg)<br> &nbsp; &nbsp; LongitudeDeg - the longitude of the sampling location (deg east)</p> <p>The paper&#39;s abstract is:&nbsp;</p> <p>Long Island Sound (LIS) is a large estuary on the eastern United States coast. Seasonal variations&nbsp;<br> in solar insolation and wind create an annual water temperature cycle that impacts circulation&nbsp;<br> and biological processes. The waters warm from March-February until August-October and then&nbsp;<br> begins to cool. Ship surveys show that the vertical temperature structure becomes uniform during&nbsp;<br> this season when the area experiences low air temperatures and high winds. However, there have&nbsp;<br> been no observations that resolve the temporal evolution of the vertical structure of temperature&nbsp;<br> during these cooling periods because conditions inhibit ship operations. We report glider&nbsp;<br> measurements of the vertical structure of water temperatures and salinities from October 22 to&nbsp;<br> November 4, 2014, in eastern LIS. We find that 20m of water can cool at approximately 0.5&nbsp;<br> C/day intervals of cold air and strong winds. We use the data to estimate heat content tendencies&nbsp;<br> and infer surface fluxes. We also estimate the surface heat fluxes using buoy-mounted&nbsp;<br> instruments and the COARE 3.0/3.5 formulae and show they are consistent. Using the buoy&nbsp;<br> fluxes and the products of an operation regional model, we show the agreement with the heat&nbsp;<br> budget fluxes is best when the closest buoy and the model results are used. This suggests that&nbsp;<br> resolving the temporally and spatially structure of the wind field is crucial to the accurate&nbsp;<br> simulation of the temperature variability in LIS. These intervals of very rapid cooling can lead to&nbsp;<br> significant density gradients between LIS and the shallow bays and marshes that surround it.</p>